FAT IN THE PREDICTION OF BONE STRENGTH OF PORCINE LUMBAR VERTEBRAE BYQUANTITATIVE COMPUTED-TOMOGRAPHY

The influence of fat content on quantitative computed tomography (QCT) values was studied using porcine lumbar vertebrae as a model. A total of 72 cancellous bone columns, prepared from 18 vertebrae, underwent QCT examination before and after defatting. Mechanical testing and ash ing were performed to obtain the ultimate strength and bone mineral co ntent. The ultimate strength was calculated as a power function of app arent density using linear regression on a log-log plot and the power coefficient was 1.88. QCT values were positively correlated with bone density. QCT values of defatted specimens correlated much better with ultimate strength than those of fresh specimens. The average fat conte nt was 27.2%. The QCT values decreased linearly with increasing fat co ntent with a slope of 7.9 mg/Cm-3/% fat and a correlation coefficient of 0.65. The results provided basic data for the calibration of the ma chine and the principles for the interpretation of QCT values excludin g the fat influence.